Ethyl cinnamate, preparation reactions

It is prepared by treating ethyl cinnamate with peracetic acid [212] or by condensation of benzaldehyde with ethyl chloroacetate (in the above Darzens reaction, R = H). The glycidate is used as a long-lasting fragrance material for creating harmonic, fruity notes in household and fine fragrances. 

Cognate preparations. Phenylpropynoic acid. Place a solution of 88 g (84 ml, 0.5 mol) of ethyl cinnamate (Expt 6.137) in 50 ml of carbon tetrachloride in a 500-ml round-bottomed flask. Immerse the flask in ice and add 80 g (25.5 ml, 0.5 mol) of bromine from a separatory funnel slowly with frequent shaking. The halogen will disappear rapidly at first, but more slowly towards the end of the reaction no hydrogen bromide is evolved and the time of the addition is about 20-25 minutes. Allow the mixture to stand for 1 hour, pour the solution into a large evaporating dish and permit the excess of bromine and the carbon tetrachloride to evaporate spontaneously in the fume cupboard. The crude ethyl 2,3-dibromo-3-phenylpropanoate will remain as a solid cake this... 

Certain aromatic and heterocyclic olefinic esters ate best prepared by condensation of ethyl acetate and aromatic aldehydes by sodium sand (Claisen). Benzaldehyde in this reaction gives ethyl cinnamate, C,HsCH=CHC03C,H5 (74%). p-Methylbenzaldehyde, furfural, furylactolein, and 2-thiophenecarboxaldehyde have been condensed in a similar manner. 

Wittig reactions. Ethylene oxide can be used as the base for generation of Wittig reagents from phosphonium salts. It is often not necessary to prepare the salts thus a mixture of ethylene oxide, triphenylphosphine, and ethyl bromoacetate reacts with benzaldehyde at 25° to give ethyl cinnamate (91% yield, trans.cis = 93 7).3... 

The synthesis of pyridazine derivatives from hydrazones includes the thermal cyclization of 2-arylhydrazono-3-oxo-5-phenyl-4-pentenenitriles (readily obtained from ethyl cinnamate by condensation with acetonitrile followed by Japp-Klingemann type reactions) to l-aryl-3-cyano-6-phenyl-5,6-dihydro-4(l//)-pyridazinones (Scheme 85) <86JHC93>, and base-induced cyclization of a hydrazone of a 4-chloro-l-arylbutan-l-one to prepare a 2,3,4,5-tetrahydropyridazine (Scheme 85) <88JHC1543>. An earlier route to 6-carboxy-5-hydroxy-2-phenyl-3(2//)-pyridazinone via condensation of benzenediazonium chloride and dimethyl acetonedicarboxylate has been adapted to give a series of aryl derivatives either as esters (by thermal cyclization) or as acids (by cyclization with hydroxide). Both cyclizations proceed in high overall yield (Scheme 86) and decarboxylation of the acids also proceeds in high yield <89JHC169>. 

Methoxy-4,5-methylenedioxycinnamyl alcohol (46) (ref. 16, 53) and 3,4,5-trimethoxyphenylpropiolic acid (49) (ref. 54) were prepared through the scheme shown in Chart 11. 3-Methoxy-4,5-methylenedioxybenzaldehyde (44) (ref. 55) obtained from vanillin via 5-iodovanillin and 5-hydroxyvanillin was converted to the corresponding ethyl cinnamate (4 5) by means of the Horner-Emmons reaction... 

The starting materials, frans-3,4-methylenedioxycinnamyl alcohol (61a) and frans-2-methoxy-3,4-methylenedioxycinnamyl alcohol (61b) were prepared from the corresponding benzaldehyde via substituted ethyl cinnamate by means of the Horner-Emmons reaction and lithium aluminium hydride reduction. Condensation of compound (61 a) or (61 b) with compound (47) gave compound (62a) or (62b), respectively, followed by ring closure to afford compound (63a) or (63b). Intramolecular Diels-Alder reaction of compound (6 2) led to the formation of the aromatized compounds as by-product in both cases. Moreover, in the reaction of... 

As with poly(vinyl alcohol), poly(vinyl cinnamate) is prepared by chemical modification of another polymer rather than from monomer . One process is to treat poly(vinyl alcohol) with cinnamoyl chloride and pyridine but this is rather slow. Use of the Schotten Baumann reaction will, however, allow esterification to proceed at a reasonable rate. In one example poly(vinyl alcohol) of degree of polymerisation 1400 and degree of saponification of 95% was dissolved in water. To this was added a concentrated potassium hydroxide solution and then cinnamoyl chloride in methyl ethyl ketone. The product was, in effect a vinyl alcohol-vinyl cinnamate copolymer Figure 14.8)... 

As a typical example of topochemically prepared polymers, the nmr speetrum of the polymer derived from ethyl 4-[2-(2-pyrazyl)ethenyl]-cinnamate [l OEt] crystals by reaction (2), and the X-ray diffraction patterns of the same monomer and polymer are illustrated in Figs 1 and 2 (Hasegawa et al., 1989a). 

It may be suspected that the genuinely topotactic (as secured by the molecular precision of the AFM [18]) photodimerization of 2-benzyl-5-benzyli-denecyclopentanone [118] might be a good candidate for a quantitative preparative photo dimerization to give the head-to-tail anti-[2+2] dimer. Early quantitative solid-state [2-1-2] photodimerizations (most of the published mechanistic interpretations of which can no longer be accepted) are listed in [110]. These deal with the anti dimerization of acenaphthylene-1,2-dicarboxylic anhydride, the head-to-head syn dimerization of acenaphthylene-1-carboxylic acid, the syn dimerization of 5,6-dichloroacenaphthylene, and the thermally reversible head-to-tail anti dimerization of seven ( )-2,6-di-f-butyl-4-(2-aryl-ethenyl)pyrylium-trifluoromethanesulfonates. All of these reactions proceed fully specific. On the other hand, quantitative photoconversions of a 1 1 mixed crystal of ethyl and propyl a-cyano-4-[2-(4-pyridyl)ethenyl]cinnamates gives mixtures of diesters with one (A>410 nm) or two cyclobutane rings (no cutoff filter). 

A somewhat different route is used to prepare an analogue that bears additional oxygen. The sequence, in this case, starts by base-catalyzed formylation of the hydro-cinnamic acid derivative (40-1) with ethyl formate. Condensation of the product (40-2) with guanidine in this case leads to a pyrimidone (40-3), with the cyclization involving an ester-amide interchange between guanidine and the ester. Reaction of... 

Other preparations of 2-iminothiazolidin-4-ones which are discussed in the review by Brown139 utilize the reactions of thiourea with a-hydroxy acids,146 ethyl diazoacetate,73 glycidic esters,74,147 cinnamic acid,148 unsaturated diacids (fumaric, maleic, and citraconic) or their esters or imides,149-152 and propiolic esters.153,154 There has been considerable controversy in the literature surrounding the propiolic ester synthesis since many workers have proposed that the products are 1,3-thiazines (see Section IV, B, 1). The pertinent papers in this controversy have been summarized by Cain and Warrener.155 Nagase158 has recently settled the argument in favor of the 2-iminothiazolidin-4-... 

Ethyl <7-nitrophenylpyruvate and < -nit ophenylpyruvic acid have been prepared by condensation of o-nitrotoluene with diethyl oxalate in the presence of potassium ethoxide, - sodium ethoxide, " or sodium methoxide. Sodium ethoxide is less reactive, however, and cannot be substituted successfully for potassium ethoxide in the present procedure, as it gives a very poor yield and poor quality of precipitated sodium salt. With sodium ethoxide the reaction does not appear to go to completion even under the conditions of refluxing ethanol usually employed,which are considerably more severe than the room temperature conditions employed with potassium ethoxide in the present procedure. a-Nitrophenylpyruvic add has also been prepared by hydrochloric acid hydrolysis of o-nitro-a-acetamino-cinnamic azlactone. ... 

Phenylpropiolic Acid, CeHs.C C.COOH, may be prepared from cinnamic acid by the reactions which are commonly employed to establish a triple bond in a compound. It is obtained by adding bromine to the ethyl ester of cinnamic acid, and subsequent elimination of hydrogen bromide by alcoholic potassium hydroxide —... 

In the laboratory, styrene can be prepared by the decarboxylation of cinnamic acid, as shown in Reaction 1, using dry distillation. However, styrene is produced commercially from ethylene and benzene, two basic ingiedienis of the petrochemical industry. With electrophilic addition of ethylene to benzene, a mixture of ethyl benzene and diethylbenzene is obtained as own in Reaction 2. The dehydrogenation of these benzene derivatives produces slyrene and divinylbenzene, respectively (Reaction 3). A detailed synthesis of styrene is described by Berthelot et al (6). As mentioned earlier, styrene is an important monomer in many industrial polymers. Additionally, divinylbenzene which is produced as a by-product is an effective crosslinker for ion-exchange resins, polystyrene-based supported reagents and catalysts, and low profile additive in a number of liquid molding resin systems. 

PAL activity is assayed spectrophotometricaUy based on the methods of Koukol and Conn (1961) and Kataoka et al. (1983) by measurement of the rate of formation of t-cinnamic acid as the increase in absorbance at 268 nm. The reaction mixture consists of 2 ml of the enzyme preparation and 1ml of 25 pm l-phenylalanine. In the reference mixture, the L-phenylalanine solution is replaced by distilled water. The mixture is incubated at 37 °C for 3h with shaking. The reaction is stopped by the addition of 0.1 ml of 6 N HCl. After 5 ml of peroxide-free ethyl ether is added, the mixture is shaken again vigorously for extraction of the acidified fraction and then centrifuged at 3000 g for 5 min. The ether phase is obtained with a pipette, and the ether is evaporated to dryness under reduced pressure. The residue is dissolved in 4 ml of 0.05 N NaOH and the absorbance of the solution at 268 nm in a 1-cm quartz cell is measured. The enzyme activity is expressed as micromoles of t-cinnamic acid formed per g FW or per mg protein in fresh tissue/h. The reaction product is scanned with a spectrophotometer for comparison of its optical characteristics with those of authentic t-cinnamic acid. The absorption spectrum of the reaction product was identical with that of authentic f-cinnamic acid (Fig. 3). 

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